Interactive input systems that allow users to inject input (e.g. digital ink, mouse events, etc.) into an application program using an active pointer (eg. a pointer that emits light, sound or other signal), a passive pointer (eg. a finger, cylinder or other object) or other suitable input device such as for example, a mouse or trackball, are well known. These interactive input systems include but are not limited to: touch systems comprising touch panels employing analog resistive or machine vision technology to register pointer input such as those disclosed in U.S. Pat. Nos. 5,448,263; 6,141,000; 6,337,681; 6,747,636; 6,803,906; 7,232,986; 7,236,162; 7,274,356; and 7,532,206 assigned to SMART Technologies ULC of Calgary, Alberta, Canada, assignee of the subject application, the contents of which are incorporated by reference in their entirety; touch systems comprising touch panels employing electromagnetic, capacitive, acoustic or other technologies to register pointer input; tablet and laptop personal computers (PCs); personal digital assistants (PDAs) and other handheld devices; and other similar devices.
U.S. Pat. Nos. 6,335,724 and 6,828,959 to Takekawa et al. disclose a coordinate-position input device having a frame with a reflecting member for recursively reflecting light provided in an inner side from four edges of the frame forming a rectangular form. Two optical units irradiate light to the reflecting member and receive the reflected light. With the mounting member, the frame can be detachably attached to a white board. The two optical units are located at both ends of any one of the frame edges forming the frame, and at the same time the two optical units and the frame body are integrated to each other.
Above-incorporated U.S. Pat. No. 6,803,906 to Morrison et al. discloses a touch system that employs machine vision to detect pointer interaction with a touch surface on which a computer-generated image is presented. A rectangular bezel or frame surrounds the touch surface and supports digital imaging devices at its corners. The digital imaging devices have overlapping fields of view that encompass and look generally across the touch surface. The digital imaging devices acquire images looking across the touch surface from different vantages and generate image data. Image data acquired by the digital imaging devices is processed by on-board digital signal processors to determine if a pointer exists in the captured image data. When it is determined that a pointer exists in the captured image data, the digital signal processors convey pointer characteristic data to a master controller, which in turn processes the pointer characteristic data to determine the location of the pointer in (x,y) coordinates relative to the touch surface using triangulation. The pointer coordinates are conveyed to a computer executing one or more application programs. The computer uses the pointer coordinates to update the computer-generated image that is presented on the touch surface. Pointer contacts on the touch surface can therefore be recorded as writing or drawing or used to control execution of application programs executed by the computer.
U.S. Patent Application Publication No. 2007/0089915 to Ogawa et al. discloses a position detection apparatus that has imaging sections, each of which includes an area image sensor, in which light-sensitive elements are arrayed in a two-dimensional pattern, and an image formation lens, are placed to the lateral two points of a detection plane. A selection device selects particular pixels corresponding to a particular field of view of a reflex reflection frame from the light-sensitive elements within a range of a given field of view having been imaged by the imaging sections. An image processing device image-processes a particular image signal corresponding to the selected particular pixels and then outputs an indicating position coordinate of a pointing device.
Certain models of interactive whiteboards sold by SMART Technologies ULC under the name SMARTBoard™, that employ machine vision technology to register pointer input, make use of imaging devices that have housing assemblies, and that select a subset of pixels of acquired images for processing to compensate for mechanical alignment issues. For example, U.S. Patent Application Publication No. 2009/0278795 to Hansen et al. assigned to SMART Technologies ULC discloses one such housing assembly. Although selecting pixel subsets of acquired images to correct for mechanical issues works well, improvements to enhance performance with regard to pointer imaging and power savings are desired.
It is therefore an object of the present invention at provide a novel interactive input system and a method of operating the same.